How to Install Ubuntu 13.10 on an external hard drive

Installing Ubuntu 13.10 on an external hard disk drive (HDD) connected to a computer that’s already running another operating system like Windows 7/8 or another Linux distribution is the subject of this article.

Installing Ubuntu or any other Linux distribution in standalone mode on an HDD is normally a simple, point-and-click operation. To do it on an external HDD connected to a computer running another operating system require a little bit more care, if you don’t want to overwrite the contents of the internal HDDs Master Boot Record (MBR). It’s still a simple process, but you have to watch out!

This tutorial gives those new to Ubuntu and Linux a step-by-step guide on how to complete what should be an easy task. The computer to which the external HDD used for this tutorial is running a self-installed copy of Windows 8. And note that the result of this operation is not the same thing as dual-booting, even though the Ubuntu installer will append an entry for the internal HDDs OS to the boot menu of the external HDD.

To start, you, of course, need an external HDD connected to the computer you are going to use and an installation image of Ubuntu 13.10, which is available for download here. Burn the downloaded image to a CD/DVD or transfer it to a USB stick. To avoid wasting a CD or DVD, transferring it to a USB stick is the recommended option. See Install Ubuntu 13.10 using a USB key from Window or another Linux distribution if you need help with that.

One last thing: Set the computer to boot from an external media. Reboot (the computer) and let’s get started. By the way, if you are new to disk partitioning in Linux, read guide to disks and disk partitions in Linux. It will make it easier to understand what you will be doing.

1. Installation Requirements: When you boot from the installation disc or USB stick, you are given the option of booting into a Live desktop or straight to the installer. Which ever option you choose, click past the first step of the installer to get to the step shown in this screen shot. You may opt to enable the two choices available at this step. Continue.

2. Be Aware!: You need to click Yes here. Why? Because sdb is the external HDD, which is the target device.

3. Partition Methods: This step shows available partition methods. As noted earlier, the computer used for this tutorial is running Windows 8 on the internal HDD. And I have two Linux distribution – in dual-boot fashion, on the external HDD. What all that means is that I’ll need to be doing a manual partitioning of the target HDD. That is the only way you can be sure that you will not be erasing the contents of the internal HDD. So, click on the Something else option. Continue.

4. Advanced Partitioning Tool: That will bring you to the Advanced Partitioning Tool’s window. This step shows all the HDDs detected by the installer and their partitions. For the computer used in this tutorial, there are just two HDDs – sda and sdb. The target HDD is sdb, so don’t touch any of sda’s partitions.

5. Erase Unwanted Partitions: This screen shot shows all the partitions on sdb. You can see that there are two Linux distributions on it already. Since I don’t need them, the task here is to delete all of its partitions. To delete a partition, simply select it and click the – button on the lower-left corner.

All partitions have been deleted, time to create partitions for Ubuntu 13.10. Notice that the size of the external HDD is 320 GB. However, I do not intend to use all that disk space for Ubuntu 13.10, just about half of it. With regards to creating the partitions, the goal is to create the same set of partitions on a default installation of Ubuntu 13.10. That means creating just two partitions; the main partition mounted at / (root) and a Swap partition.

6. Partition Editor: This is the partition editor’s window. With no existing partitions on the HDD, the installer will set up the options to create a primary partition. And that’s just fine, at least for the first partition. The only fields you need to change are the size and mount point. The default file system is ext4, which you don’t need to change unless you have a specific reason to.

7. Create Root Partition: For the root partition, I chose to allocate 150 GB to it. This is just an example. Assign whatever you think is appropriate for your installation, keeping in mind that the minimum disk space required is just under 6 GB. Select the mount point as shown and click OK.

8. Back to the main partitioning window, the partition just created should be listed below sdb. Select the free space and click the + button.

9. Back here again. By default, the installation will want to create the next partition as a logical partition. That, too, is fine. However, I chose to create the Swap partition as another primary partition. Whether the partition is primary or logical will have no impact on the system, so if you don’t want to mess with the default, don’t.

10. Create Swap Partition: So I allocated the Swap partition just 2000 MB (2 GB). That should be more than enough for any desktop system. Select swap area from the “Use as” menu and click OK.

11. Back to the main partitioning window, you see the two partitions you just created. Notice also that I left a lot of free space unallocated. I didn’t have to, just did it in case I have to create an extra partition after installation. This free space could also be used to create a shared NTFS partition.

The most important thing you need to do here is ensure that the external HDD is the device where the boot loader will be installed. You do that by selecting /dev/sdb from the menu.

12. Install Now: Here’s the menu just before you click Install Now.

After installation, reboot and verify that the installer did not mess with the MBR of the internal HDD. If you can boot from it, you are good to go. And if you see an entry for the OS on the internal HDD in the boot menu of the external HDD, all is good, too.